Action Mailer is a framework for designing email-service layers. These layers are used to consolidate code for sending out forgotten passwords, welcome wishes on signup, invoices for billing, and any other use case that requires a written notification to either a person or another system.
Action Mailer is in essence a wrapper around Action Controller and the Mail gem. It provides a way to make emails using templates in the same way that Action Controller renders views using templates.
Additionally, an Action Mailer class can be used to process incoming email, such as allowing a weblog to accept new posts from an email (which could even have been sent from a phone).
The framework works by initializing any instance variables you want to be available in the email template, followed by a call to mail to deliver the email.
This can be as simple as:
class Notifier < ActionMailer::Base delivers_from '[email protected]' def welcome(recipient) @recipient = recipient mail(:to => recipient, :subject => "[Signed up] Welcome #{recipient}") end end
The body of the email is created by using an Action View template (regular ERB) that has the instance variables that are declared in the mailer action.
So the corresponding body template for the method above could look like this:
Hello there, Mr. <%= @recipient %> Thank you for signing up!
And if the recipient was given as “[email protected]”, the email generated would look like this:
Date: Mon, 25 Jan 2010 22:48:09 +1100 From: [email protected] To: [email protected] Message-ID: <[email protected]> Subject: [Signed up] Welcome [email protected] Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII"; Content-Transfer-Encoding: 7bit Hello there, Mr. [email protected]
In previous version of Rails you would call create_method_name and deliver_method_name. Rails 3.0 has a much simpler interface, you simply call the method and optionally call deliver on the return value.
Calling the method returns a Mail Message object:
message = Notifier.welcome # => Returns a Mail::Message object message.deliver # => delivers the email
Or you can just chain the methods together like:
Notifier.welcome.deliver # Creates the email and sends it immediately
Sometimes you have an Action Mailer class with more than one method for sending e-mails. Think of an authentication system in which you would like to send users a welcome message after sign up, a forgot your password message and a message to send when the user closes his account. Your class would look something like this.
Example:
class Authenticationmailer < ActionMailer::Base
def signed_up(user)
# prepare the view
....
# and send the e-mail
mail(:to => user.email,
:subject => "Welcome to our awesome application!",
:from => "[email protected]")
end
def forgot_password(user)
# prepare the view
....
mail(:to => user.email,
:subject => "Forgot your password? No worry, we're awesome at that too!",
:from => "[email protected]")
end
def closed_account(user)
# prepare the view
....
mail(:to => user.email,
:subject => "Closing your account, are you? That's not awesome, dude!",
:from => "[email protected]")
end
end
Now this works fine, but it would be nice if we could remove the :from from the method, seeing that it is a static value that is the same across all the methods, and just assign it once. Introducing the default method. With this method you can assign default values that will be used by all of the mail methods. Now you can refactor the above example to just assign the :from value only once.
Example:
class Authenticationmailer < ActionMailer::Base default :from => "[email protected]" def signed_up(user) # prepare the view .... # and send the e-mail mail(:to => user.email, :subject => "Welcome to our awesome application!") end def forgot_password(user) # prepare the view .... mail(:to => user.email, :subject => "Forgot your password? No worry, we're awesome at that too!") end def closed_account(user) # prepare the view .... mail(:to => user.email, :subject => "Closing your account, are you? That's not awesome, dude!") end end
The default method takes a Hash, so it is possible to assign more values in one method.
Example:
class Authenticationmailer < ActionMailer::Base default :from => "[email protected]", :subject => "Default subject" ..... end
The default value is overwritten if you use them in the mail method.
To receive emails, you need to implement a public instance method called receive that takes an email object as its single parameter. The Action Mailer framework has a corresponding class method, which is also called receive, that accepts a raw, unprocessed email as a string, which it then turns into the email object and calls the receive instance method.
Example:
class Mailman < ActionMailer::Base def receive(email) page = Page.find_by_address(email.to.first) page.emails.create( :subject => email.subject, :body => email.body ) if email.has_attachments? for attachment in email.attachments page.attachments.create({ :file => attachment, :description => email.subject }) end end end end
This Mailman can be the target for Postfix or other MTAs. In Rails, you would use the runner in the trivial case like this:
rails runner 'Mailman.receive(STDIN.read)'
However, invoking Rails in the runner for each mail to be received is very resource intensive. A single instance of Rails should be run within a daemon, if it is going to be utilized to process more than just a limited number of email.
The Base class has the full list of configuration options. Here’s an example:
ActionMailer::Base.smtp_settings = { :address => 'smtp.yourserver.com', # default: localhost :port => '25', # default: 25 :user_name => 'user', :password => 'pass', :authentication => :plain # :plain, :login or :cram_md5 }
The latest version of Action Mailer can be installed with Rubygems:
% [sudo] gem install actionmailer
Source code can be downloaded as part of the Rails project on GitHub
Action Mailer is released under the MIT license.
API documentation is at
Bug reports and feature requests can be filed with the rest for the Ruby on Rails project here: